(1) Field of the Invention
The invention relates to a leg prosthesis, consisting of a prosthesis shaft with a prosthesis shaft adapter non-releasably integrated therein and a transtibial part with a foot and a knee joint part or a transtibial part with a foot, wherein the prosthesis shaft and the transtibial part are releasably connected with each other by way of the prosthesis shaft adapter.
(2) Description of Related Art
Leg prostheses and prosthesis shaft adapters producing a suitable mechanical connection between the prosthesis shaft and the transtibial part of a leg prosthesis are known. Frequently, a so-called inner shaft, or liner, made of a soft flexible material, for example silicone, is used in the hollow space of the prosthesis shaft for direct skin contact and as adhesion promoter on the skin. The lower closed end of the liner has a metal pin which is connected to the liner over a large area, wherein the pin can be locked with the liner through an opening in the lower prosthesis part and fixed in this position.
For applying the liner on the amputation stump, the liner is rolled up on the amputation stump and then inserted into the actual prosthesis shaft and connected and locked by the metal pin with an adapter in or on the prosthesis shaft for securing the liner on the knee joint component.
For removing the liner, the lock is released again and the amputation stump with the liner is pulled out of the prosthesis shaft and rolled down.
For realizing this mechanical process, at least one additional adapter is required on the alignment line between the hip joint and the midfoot for vertical biostatic force flux equalization. In practice, however, several adapters are frequently required for shifting the coupling location or the connection location to the knee joint of the transtibial part back.
Disadvantageously, several adapters may be required for shifting or returning the connection between the prosthesis shaft and the knee joint of the transtibial part due to the size of the patient and the length of the amputation stump. However, the overall height is determined by the patient and is frequently not adequate for the system to enable a proper fit. Alternatively, very expensive custom-built designs need to be considered.
When using several adapters, their relatively high weight and an increased accident risk due to the large number of components and the costs for these components are disadvantageous (U.S. Pat. No. 5,888,234; U.S. Pat. No. 5,507,837; U.S. Pat. No. 7,083,654; U.S. 2011-0015761 A1).